In certain side-channel attacks, information relating to the timing and/or power consumption of computations may be used to compromise the security of a secure data system.
US Patent Application Publication 2012/0204056, whose disclosure is incorporated herein by reference, describes a data processing apparatus that is configured to perform a data processing operation on at least one data value in response to a data processing instruction. The data processing apparatus comprises a delay unit situated on a path within the data processing apparatus, wherein the delay unit is configured to apply a delay to propagation of a signal on the path and propagation of that signal forms part of the data processing operation. The data processing apparatus is configured to determine a result of the data processing operation at a predetermined time point, wherein the predetermined time point following an initiation of the data processing operation by a predetermined time interval. The delay unit is configured such that a time for the data processing operation to be performed plus the delay is less than the predetermined time interval.
US Patent Application Publication 2011/0285421, whose disclosure is incorporated herein by reference, describes a technique and method for reducing ability to monitor the relationship between currents in the system and the data in the system by closing the overall clock eye diagram, whilst keeping the eye diagram for connected stages open. The degree of eye closure for connected pipeline stages allows the system to run closer to its maximum operating speed compared to the use of system wide clock jitter, yet the overall closure provides security that is absent from systems with a partially open eye.
U.S. Pat. No. 8,427,194, whose disclosure is incorporated herein by reference, describes a technique and methods for reducing the ability of an intruder to monitor the relationship between currents in the system and the data in the system through the use of a randomized clock wherein the clock eye diagram is closed and without significant reduction in maximum operating speed compared to the reduction in maximum operating frequency that occurs when using conventional means of additive jitter.